FATIGUE THRESHOLDS AND DUCTILE-BRITTLE TRANSITIONS IN Ti-30Mo

— Substantial effects of hydrogen are found on the DBTT and cleavage fracture stress in both cathodically and gas phase charged samples of a BCC Ti alloy. Fatigue thresholds when plotted as a function of temperature exhibit a peak and this peak shifts towards higher temperatures when the hydrogen level is increased. An elastic calculation of static threshold stress intensities using experimentally observed fracture stress parameters show a similar trend to fatigue threshold stress intensities.